Subtilisin cleavage of human growth hormone enhanced the growth promoting activity of the hormone. This enzymatically modified form will be characterized for different biological activities, such as mobilization of fatty acids, and production of glucose intolerance. A newly recognized form of growth hormone, thought to be an allelic modification, will be studid chemically and biologically. The growth hormone that makes up a disulfide dimer of the hormone will be studied by peptide analysis to determine if it has the same structure as monomeric growth hormone. BIBLIOGRAPHIC REFERENCES: Lewis, U.J., Pence, S.J., Singh, R.N.P. and VanderLaan, W.P.: Enhancement of the Growth Promoting Activity of Human Growth Hormone. Biochem. Biophys. Res. Comm. 67:617 (1976). Lewis, U.J., Singh, R.N.P., Peterson, S.M. and VanderLaan, W.P.: Human Growth Hormone, a Family of Proteins. In: Growth Hormone and Related Peptides. (A. Pecile and E.E. Muller, eds), Excerpta Medica International Congress Series 381, Excerpta Medica, Amsterdam, 1976, pp 64-74.